High speed valves



March 19, 1968 R. sM|| GEs ET AL HIGH SPEED VALVES Filed Jan. 4, 1963 es60 7| 6| es e4 5| 3 Sheets-Sheet l 7| llO |07 lll 65 |06 6o H2 5| 54 s74 56 67 |05 MQ g?, r 9% 52o 34 nl m .W 44 |oo |04 \37 I| v 3o :73 35|03 lol |02 Iig... E' v INVENTORS.

JOSEPH H. CASLOW ROBERT SMILGES OD,4 HERRON 8 EVANS March 19, 1968 R,SMlLGEs ET AL y 3,373,763

HIGH SPEED VALVES Filed Jan. 4, 1963 5 Sheets-Sheet 2 INVENTORS.

JOSEPH Hp CASLOW ROBERT sM/LGES f .F.zg.. .ZJ BY wooo, HERRoNa EVANSMarch 19, 1968 RSMILGES vFTM l 3,373,763

HIGH SPEED VALVES Filed Jan. 4, 1963 3 Sheets-Sheet 3 INVENTORS ROBERTSM/LGES JOSEPH H CASLOW BY WOOD, HERRON EVANS A 7' TOENE YS UnitedStates Patent C) 3,373,763 HIGH SPEED VALVES Robert Smlges and Joseph H.Caslow, Columbus, Ohio, assignors to American Brake Shoe' Company, NewYork, N.Y., a corporation of Delaware Continuation-impart of applicationSer. No. 102,824, Apr. 13, 1961. This application Jan. 4, 1963, Ser. No.

20 Claims. (Cl. 137-269) pending application Ser, No. 102,824, tiledApr. 13, 1961,

and since abandoned.

A principal objective of the present invention has been to provide avalve construction which is capable of high speed response to changesfrom a predetermined hydraulic condition, but which is also adapted tobe manufactured at minimum cost in a wide variety of sizes. Prior to thepresent invention, complete hydraulic valves of various sizes for eachpredetermined type of service have been manufactured. Each such valvehas had a multiplicity of parts some of which may be identical infunction to similar parts of other 4valves of different flow capacitiesor of different pressure capabilities. Though of like function in theirrespective valves, similar parts of such valves have differedappreciably in size. For example, a hydraulic system in which uid flowsin relatively small volume may be served by, say, 3A inch valve, whereasanother system intended to operate at the same pressure may include alarge hydraulic motor for which a two inch valve is required in order tocarry the volume of uid needed for proper operation of the large motor;the two valves may thus be comparable in pressure rating but differ asto size, It is apparent that the valve manufacturer has not only had tomaintain a large inventory of complete valves of different sizes but hasalso had to manufacture a wide variety of sizes of the parts needed forthe assembly of each type of valve in the different size ranges. On thisaccount, it is not practical to use the most economical types of highproduction tooling suited for large quantity runs.

The present invention contemplates a series of valves of differentsizes, types and hydraulic functions, which are uniform from valve tovalve as to the hydraulic control members which the valves contain, suchthat the critical elements which must be precisely machined, i.e., themovable valve members and associated parts, may be manufactured with thegreatest economy in large production runs. According to the invention,different valves in the series are characterized in that the bodiesthereof, including inlet and outlet ports, differ from valve to valveaccording to the ow requirements, pressure ratings, and type of mountingin the systems in which the valves are to be installed, but also in thatthe valve bodies contain chambers which are uniform in size from valveto valve regardless of body construction. Such chambers communicate withthe inlet and outlet ports of the bodies and contain the main movablevalve elements through which valve opening or closing is effected, whichvalve elements are likewise uniformly sized. Eachvalve body alsocontains one or more fluid passageways terminating in a face which isadapted to receive a cap assembly containing pressure responsiveelements through which opening and closing of the main valve members inthe chamber of the body is determined to effect various controlfunctions, and

ICC

such cap elements are usable with all of the valve bodies of the seriesregardless of their individual characteristics. By this means it isapparent that a valve manufacturer is enabled to establish largeproduction runs on pieces of uniform size and thereby eliminate theinefficiency involved in short production runs of a Wide variety ofpieces.

In order to enable these concepts of economy to be utilized, however, itisessential that valve structure be provided in which the valve elementserving the inlet and outlet ports of the largest valve in the serieswill respond uniformly and satisfactorily when controlling much' lowerflow ratesor much lower pressures or both. Heretofore, the reason thevarious operating parts of valves have been proportioned in sizeaccording to the service requirements the valves were expected to meethas been that a valve structure suitable for handling large volumes offluid at high pressure would not be equally capable of serving muchsmaller volumes of Huid or fluid at much'lower pressure or vice versa.

Thus, a second important aspect of this invention is a valve structurewhich, without variation in the size of its main operating elements, hasbeen found to display the ability to respond uniformly and reliably towidely different ow rates and pressures. More specifically,thisinvention is predicated in part upon a valve construction in which ahigh rate of response is obtained upon variation of pressure from apredetermined condition whether the flow rate or pressure is large orsmall. According to this invention, the chambersof all the valve bodiesof the series, and the main valve members contained in such' chambers,are suiciently large to accommodate the maximum flow and pressureexpected of the largest valve of the series, but are so constructedAthat lthey are equally capable of accommodating the smal-lest flow atthe lowest pressure expected to be served by the smallest valve of theseries.

In more particular detail, the objective of this invention has been toprovide a valve having a chamber communicatingvwith inlet and outletports, a valve member movable in the chamber and having an endwiseportion` forming a closure with the inlet port for limiting escape offluid from the outlet port thereof, but also movable to open position inresponse to variation of pressure from some predetermined pressure. Thevalve member is biased to closed position when the predeterminedpressure conditiony exists,

but is maintained in hydraulic balance by pressure exerted at the endthereof opposite the seating end, through uid admitted thereto through apassage. The relief of uid pressure from this end of the valve isprovided by control elements responsive to pressure, which elements arecontained in a cap, as subsequently described. The invention thusprovides a valve capable of being used within a wide range ofrequirements, and this characteristic, in turn, enables a level ofstandardization ofl manufacture which has not heretofore been possible.

The Ivalve members of a valve in accord-ance with this invention are socontgurated that in open position, the' movable Valve member is insubstantial hydraulic balance but in closed position presents an area toclosing pressure slightly exceeding, preferably by about 0.5% to about6% or more, the area` which it then presents to opening pressure. Themovable valve member is preferably in the form of a cylinder having aconical taper at its seating end, the taper forming anangle greater thanabout 10 and less than about 30' with the axis of the cylinder.

Another objective of this invention has been the provision of optionalmeans in the valve for preventing the valve from opening inresponse toan excess of pressure at its outlet port with respect to its inlet port,whereby 3 the valve is adapted for use in systems wherein the valve issubjected to reversed pressure conditions.

Valves constructed in accordance with the foregoing principles areillustrated in the accompanying drawings in which:

FIGURE 1 isa vertical cross-section of a 5,000 p.s.i. 3r-inch reliefvalve embodying the principles of the invention, including a bodyadapted to be subplate mounted, closure-forming members received by achamber in the body, and a cap which is mounted to the body and whichcontains a pilot valve whereby the main closureforming members arecaused to release or relieve pressure in excess of a predeterminedvalue;

FIGURE 2 is a vertical cross-section of the body of a 5,000 p.s.i. 3%;-inch threaded valve which is adapted for use with the `cap andclosure-forming members shown in FIGURE 1;

FIGURE 3 is a vertical cross-section of the body of a 5,000 p.s.i.2-inch flange mounted valve which is adapted for use with the cap andclosure-forming members shown in FIGURE 1;

FIGURE 4 is a vertical cross-section of the body of a 5,000 p.s.i.2-inch subplate mounted valve which is adapted for use with the cap andclosure-forming members shown in FIGURE 1;

FIGURE 5 is a vertical cross-section of a 5,000 p.s.i. M1-inch sequencevalve including a body adapted to be subplate mounted, closure-formingmembers similar to those shown in FIGURE 1, and a cap structure which isgenerally similar to that of FIGURE 1 but which is modified to cause themain closure-forming members to open at a predetermined pressure anddirect flow at substantially that pressure to an outlet;

l FIGURE 6 is a vertical cross-section of a 5,000 p.s.i. ll/z-inchunloader valve including a body adapted to be subplate mounted,closure-forming members similar to those shown in FIGURES 1 and 5, and acap structure mounted to the body which contains a pilot valve where-Iby the main closure-forming members are caused to open at apredetermined control pressure which is independent of the pressureacting on the main closure members;

FIGURE 7 is a vertical cross-section of a 3,000 p.s.i. %inch reliefvalve including a body adapted to be subplate mounted, closure-formingmembers of the type shown in FIGURES 1, 5 and 6 which are received in achamber formed in the body, and a cap structure mounted to the bodywhich contains a pilot valve whereby the main closure members are causedto relieve pressure in excess of a predetermined value;

FIGURE 8 is a vertical cross-section of the body of a 3,000 p.s.i.M1-inch threaded valve which is adapted for use with the cap andclosure-forming members shown in FIGURE 7;

FIGURE 9 is a vertical cross-section of the body of a 3,000 p.s.i.ll/z-inch subplate mounted valve which is adapted for use with the capand closure-forming members shown in FIGURE '7;

FIGURE l0 is a lVertical cross-section of the body of a 3,000 p.s.i.ll/z-inch threaded valve which is adapted for use with the cap andclosure-forming members shown in FIGURE 7;

FIGURE 11 is ayvertical cross-section taken on line 11-11 of FIGURE 10;

FIGURE 12 is an enlarged cross-section of a portion of the mainclosure-forming elements illustrating a preferred construction thereofin accordance with the invention; and

FIGURE 13 is a vertical cross-section of a relief valve embodying theprinciples of the invention and including novel check valve meansincorporated in a sandwich plate between the valve body and cap, wherebythe valve is prevented from opening in response to an excess of pressureat its normal outlet port.

All of the valve bodies illustrated in FIGURES l-ll receive mainclosure-forming elements of the type shown 4 in FIGURE 1 and describedmore fully hereinafter, whereby those elements can be used in valves ofvarious pressure ratings, ow capacities, and mountings. Moreover, thesevalve bodies may be fitted with any of several different cap structuresto provide, with slight modification of the body, various controlfunctions.

For example, the valve bodies illustrated in FIGURES 1-6 are capable ofhandling pressures up to 5,000 p.s.i., while the valve bodies shown inFIGURES 7-11 are capable of handling lesser pressures up to 3,000 p.s.i.The bodies of FIGURES 1, 2, 5, 7, and 8 are for use with 3A- inchpiping, the bodies of FIGURES 6, 9, l0 and ll are for use with ll/z-inchpiping, while FIGURES 3 and 4 illustrate valve bodies for use with twoinch piping. Various types of mounts are illustrated, the valve bodiesof FIGURES 1, 4, 5, 6, 7, and 9 being adapted for mounting to aconventional subplate, those of FIGURES 2, 8, 10 and 1l being adapted toreceive threaded piping, while the valve body shown in FIGURE 3 is forange mounting. The cap structures shown in FIGURES 1 and 7 providerelief valve control function, while the cap structures shown in FIGURES5 yand 6 respectively provide sequence and unloader control functions.As previously explained, by reason of this inter-changeability of partsthe valve manufacturer is enabled to supply a series of valves fordifferent requirements by producing relatively few components.

In FIGURE l, a relief valve is shown which includes a body 20 having aninternal chamber 21 in the form of a central downwardly extending bore.Chamber 21 cornmunicates coaxially at its lower end with an inlet port22, and communicates laterally with an outlet port 23. Outlet port 23curves downwardly from chamber 21 and extends to the flat lower face 24of body 20 at a position spaced from inlet port 22. A vertical passage25 extends between the lower face 24 and the upper face 26 of body 20,and communicates with inlet port 22 through a transverse passage 27.This passage 27 is closed at its outer end by a plug 30, and is providedwith a reduced orifice 31 between vertical passage 2S and inlet port 22.The flat lower surface 24 of body 20, which inlet port 22, outlet port23 and vertical passage 25 meet at spaced positions, is adapted to betted to a standard subplate mount provided on hydraulic equipment orpiping, fluid seals being provided by appropriate means such as theO-rings shown.

A cylindrical groove 32 is formed in chamber 21 adjacent outlet port 23.A sleeve 33 is fitted into chamber 21 and is held therein by the capstructure to be described. This sleeve 33 is provided with an internalgroove 34 from the lower wall of which a seat 35 having the form of aright angular shoulder extends inwardly adjacent inlet port 22. Groove34 in sleeve 33 communicates with groove 32 of chamber 21 through spacedports 36. The internal angular edge of the shoulder presented by seat 35cooperates in line contact with a movable poppet or piston 37 more fullydescribed hereinafter to form a valve between inlet port 22 and groove34. Groove 34 in turn communicates through ports 36 to outlet port 23.

Cylindrical poppet 37 is slidably received within sleeve 33. Poppet 37is provided with a downwardly extending bore 40, and a plug 41 isthreaded into an opening at the lower end of poppet 37. As is best shownin FIGURE 12, the peripheral lower edge 42 of poppet 37 is conicallytapered or angulated, preferably at an angle of about 10 to about 30with respect to the axis of the poppet. An angle of about 20 is mostadvantageous. This angulated surface 42 cooperates in line contact withthe edge of seat 35 to from a valve.

Spaced circumferential grooves 43 are formed around the upper portion ofpoppet 37 to form a sliding seal with sleeve 37. A low-rate spring 44 isdisposed in the internal chamber 45 within poppet 37 and urges thepoppet toward the position shown, in which surface 42 bears upon seat 35in line contact therewith. Spring 44 may, by way of example, urge poppet37 toward closed position with a force in. the range of 30 to 50 pounds,although this is not critical..

We have empirically determined that the operation of the valve issubstantially improved, particularly in respect to reduction of leakage,if the cross-sectional area of poppet 37 is about 0.5% to about 6%greater than the internal area within the edge of seat 35. Otherwiseput, the operation of the valve is improved if when the valve is closedthe downwardly acting force of hydraulic fluid in chamber 45 withinsleeve 33 above the poppet is slightly greater than the upwardly-actingforce of fluid at like pressure on the lower fact of poppet 37, wherebya slight net closing force will then exist. When valve 35, 42 is open,however, the upwardly and downwardly facing areas of poppet 37 exposedto pressure will be equal, so that the poppet will then be insubstantial hydraulic balance.

Because of the relatively large line of contact of poppet face 42 withseat 35, slight upward axial motion of the poppet presents a relativelylarge orifice area through which fluid can pass. The poppet travelrequired to pass a large flow of fluid is not much greater than thatrequired to pass a small flow, whereby valve response is substantiallysimilar regardless of flow. Tests have confirmed that valves embodyingthis construction are substantially immune to variation in response withvelocity change and, moreover, do not evidence wire drawing.

By reason of the differential of the valve area subjected to closingpressure over the area subjected to opening pressure when the valve isclosed, a net fluid force acts to hold the valve closed, in addition tothe force of spring 44, and this force increases with the pressuretending to open the valve. Thus, the greater the opening pressure, themore tightly the valve is held closed, so that leakage at high pressuresis reduced. At low pressures, however, the force tending to hold thevalve closed is also low so that no large unbalanced forces are appliedto the edge of seat 35. When the valve is open, the areas subjected toopposing pressures are equal, the valve is in hydraulic balance, and is`biased only by spring 44, so that it can readily respond to pressurechanges.

We have also found that a taper angle of more than about and less thanabout 30 contributes to the feasibility of using a standard size poppetand sleeve in a range of valve bodies. Tests have shown that with anangle of about 10, the poppet travel required for full flow is too greatto permit satisfactory use of the poppet in a valve of large flowcapacity. On the other hand, an angle of about 30 tends to cause valvechatter at high pressures. We prefer that the angle be about at whichthe standard poppet and sleeve perform well in all of the various bodiesto be described.

A cap 50 containing structure which comprises a pilot valve is mountedto the upper face 26 of body 20 by means of screws not shown and closesthe open upper end of chamber 21. Cap 50 has a horizontal bore 51 formedin it which is closed at one end by a plug 52. Vertical passage of body20 communicates with bore 51 through a bore 53. Another vertical passageor bore 54 extends between the upper end of chamber 21 and bore 51 inthe cap, and includes a restricted orifice insert 55. Another verticalpassage 56 communicates from bore 51 to a bore 57 in body 20 which inturn communicates with outlet port 23. Fluid seals between body 20 andcap 50 are provided at all of these passageways by means of suitablegaskets such as the O-rings shown.

Between bores 53 and 54 in bore 51 there is disiposed a sleeve 60 and aguide bushing 61 which contains a reciprocable piston 62. A pilot valveseat 63 is fitted into bore 51 against a step or shoulder therein. Valveseat 63 is engaged by conical valve element 64 which is urged towardseat 63 by a coil spring 65 disposed between valve element 64 and aspring adjustment screw 66 which is threaded into a` collar 67 securedto cap 50 at the end of bore 51.

The piston 62 received in guide bushing 61 serves in the operation ofvalve 63, 64 to assist in moving valve element 64 away from seat 63.This piston 62 has a restricted passage 70 formed therethrough toestablish limited communication between section 71 of bore 51 which isto the left of bushing 61, and section 72 of bore 51 which is betweenbushing 61 and seat 63. The restricted passage 70 in piston 62 alsoprovides for a pressure drop between opposite ends of the piston whenfluid is permitted to flow past valve element 64. The right end ofbushing 61 is reduced so that bore 54 communicates with section 72 ofbore S1.

When fluid pressure is applied to the lower face 73 of poppet 37 atinlet port 22, some of this fluid will flow in transverse passage 27through orifice 31 into vertical passage 25 and communicating passage 53into section 71 of bore 51 which is to the left of guide bushing 61.Some of this fluid flows through restricted passage 70 in piston 62 tosection 72 of bore 51 between guide bushing 61 and seat 63, and throughvertical passageway 54 and orifice 55 into the chamber 45 above thelower end of poppet 37. This fluid is substantially at the pressure offluid at inlet port 22. The unbalance of opposing hydraulic forces dueto the difference in poppet areas acted on by fluid pressure, togetherwith the downward force of spring 44, maintains valve 35, 42 closed.

As the pressure in the system increases, it tends increasingly to forcevalve element 64 away from seat 63 against the counteracting force ofspring 65. When the pressure becomes so high that the fluid forcesacting on valve element 64 at seat 63 overcomes the preadjusted force ofspring 65, valve element 64 is pushed slightly away from the seat 63,and fluid flows from the space 72 in bore 51 between guide bushing 61and seat 63 to the section 74 on the other side of seat 63, from whichit is exhausted through bores 56 and S7 to outlet port 23, which in atypical system would be connected to a fluid reservoir or tank. The flowof fluid through restricted bore 70 in piston 62 causes a differentialin pressure between the ends of piston 62 to be established. In responseto the differential in pressures acting on its end faces, piston 62 ismoved toward seat 63 forcing valve element 64 still further from theseat, so that an outlet is thereby provided for fluid in chamber 45above the lower end of poppet 37. As this pressure is released, the nowrelatively high fluid pressure at the lower end 73 of poppet 37 rapidlymoves the poppet upwardly, whereby valve 35, 42 is opened and thepressure at inlet port 22 is released.

When the fluid pressure in chamber 71 drops sufficiently the forcetending to move piston 62 and valve element 64 to open position will bereduced to a point at which spring 65 can force valve element 64 backinto engagement with seat 63. This action will close the outlet fromchamber 45, and the fluid pressure therein will quickly build up to thesame pressure obtaining below poppet 37 at inlet port 22. As thesepressures approach equalization, spring `44 and fluid pressure inchamber 45 will cause the poppet to move downwardly to effect theclosure of valve 35, 42.

It will be seen from the foregoing that the precise pressure at whichvalve 35, 42 opens to relieve pressure at inlet port 22 is determined bythe force applied through spring 65 to valve element 64. This force isdetermined by the compression of the spring, which may be regulated byadjusting screw 66 in collar 67.

In FIGURE 2 there is shown a valve body 68 which differs from the valvebody 20 shown in FIGURE l in that the valve body 68 shown in FIGURE 2 isadapted to receive threaded piping. Apart from the difference in thetype of interconnection to hydraulic equipment for which it is adapted,however, the valve body lshown in FIGURE 2 is generally similar to thevalve body shown in FIGURE l, and includes an inlet port 74 whichcornmunicates with a chamber 75, a lateral outlet port 76, a transversebore 77 and vertical bores 80 and 81 which communicate from the flatupper face 82 of body 68 to transverse bore 77 and chamber 75respectively.

Chamber 75 is provided with a groove 83 which corresponds with groove 32of body 20 shown in FIGURE 1, and is adapted to receive a sleeve andpoppet assembly similar to those designated by 33 and 37 respectivelyvin FIGURE 1. Body 68 is adapted to receive the cap 50 shown in FIGURE lor the caps shown in FIGURES and 6 which are described more fullyhereinafter, bores 80 and 81 and chamber 75 of body 68 being so spacedas to communicate with the bores 53, 54 and 56 of cap 50 when the cap ismounted to the body. The valve body 63 shown in FIGURE 2 makes itpossible, in effect, to convert the subplate mounted relief valve ofFIGURE 1 into a threaded relief valve simply by inserting the sleeve 33and poppet 37 in chamber 75, mounting the cap on the upper surface 82 ofthe body, and inserting an orice and plug corresponding to orifice 31and plug 30 of FIGURE 1 into the body.

FIGURE 3 illustrates another type of valve body which is adapted forflange mounting to hydraulic pipe and which is adapted to receive thesame sleeve and poppet shown in FIGURE 1 and a cap such as shown in FIG-URES 1, 5 and 6. Whereas the valve bodies shown in FIGURES 1 and 2 arefor use with 3pinch pipe, however, the valve bodies of FIGURES 3 and 4are adapted for use with two inch pipe, even though they will receivethe same sleeve, poppet, and caps as valves of smaller capacity. Thisinterchangeability of parts in valves of different capacities ispossible because the sleeve and poppet shown in FIGURE 1 are just aseffective in their ability to handle the larger flows delivered by twoinch pipe, for example, as they are in controlling the smaller flowsdelivered by 11/2 and %inch pipe. Specifically, valve response to suddenpressure increases or decreases is substantially similar regardless ofthe flow passing through the valve.

In FIGURE 5 there is shown a valve generally similar to the valve shownin FIGURE 1 in overall construction, but which is adapted to function asa sequence valve through minor changes in `the cap structure. The body,sleeve and poppet of this valve are the same as those shown in FIGURE 1,but passage 70 of piston 62 is closed by a plug 90, bore 56 is closed bya plug 91, and horizontal bore 51 is provided with an outlet 92 which,in operation of the valve, Would normally be connected to tank.Transverse or radial inlets 79 are formed in piston 62 adjacent toplugged left end thereof, opening inwardly into passage 70.

The valve of FIGURE 5 is adapted to function as a sequence valve whichwill open at a specific inlet port pressure to direct liow to the outletport at that pressure. In the operation of the valve, fluid pressure atinlet port 22 is applied to the underside 73 of poppet 37 and, throughbore 27, orifice 31, passage 25, bore 53, and the transverse inlets 79into passage 70, to the end of conical valve element 64. When inletpressure rises to that point at which the force applied to the conicalvalve element 64 overcomes the force of spring 65, valve element 64 ismoved laway from seat 63 and the piston 62 follows the movement ofelement 64 and the transverse inlets 79 to passage 70 in piston 62 areclosed by the guide bushing 61 whereupon the pressure acting upon theclosed end 90 assumes control of element 64 and holds it olif its seat63. When this occurs, pressure in chamber 45 above poppet 37 quicklydrops. The balance of forces acting on poppet 37 then causes the valve37, 42 to open, so that liuid flows without substantial pressure drop tooutlet port 23. When pressure acting on the plugged end 90 of piston 62drops below a value determined by the compression of spring 65, thepiston 62 is moved to the left by spring 65 and opens the transverseinlets 79 to passage 70 whereby pressure inside of spool 37 in chamber45 rapidly rises due to flow through orifice 31, passages 25 and 53,section 71 of bore 51, passage 70 in piston 62, and orifice 55, until itequals inlet pressure. Spring 44 then causes valve 42, to close. Therelief valve of FIGURE 1 thus may be converted into a sequence valvesimply by mounting a cap of the type shown in FIGURE 5 on the body 20.This cap may alternatively be used on any of the other bodies showninFIGURES 1-6 to provide a sequence control function.

The valve shown in FIGURE 6 is an unloader valve which opens to releasepressure at its inlet port when a control pressure, which may bedifferent than the inlet pressure, exceeds a predetermined value. Thisvalve includes a body which receives the same main valve elements as thesubmount valve body 20 shown in FIG- URES 1 and 5, but which is adaptedfor use with 1v1/2 inch pipe. Specifically, both inlet port 101 andoutlet port 102 are larger than the corresponding ports 22 and 23 of thevalve shown in FIGURE 5, and the 'body is designed to withstand thegreater forces to which it is subjected under the greater volume offluid it handles.

A plug 103 fitted into bore 104 isolates vertical pas sage 105 frominlet port 101. The valve cap 106 differs from the cap structure 50shown in FIGURE 1 in that the piston 107 mounted by guide bushing 110 issolid, and in that the movable valve element comprises a free sphericalball 111 which is centered by a spring-loaded member 112. The section ofbore 51 between guide bushing 110 seat 63 communicates with chamber 45above poppet 37 through orifice 5S, and the chamber 74 to the right ofseat 63 communicates with outlet bore 57 through bore 56.

The operation of the unloading valve is as follows: when the controlpressure applied to the left end of piston 107 through vertical passage105 is low, spring 65 holds ball valve 111 against seat 63. The pressurebelow poppet 37 is refiected in chamber 45 above poppet 37 throughorifice 113, spring 44 holding poppet 37 in closing relation with seat35. When the control pressure becomes great enough to cause piston 107to push ball 111 away from seat 63, the pressure above poppet 37 quicklydrops, causing the valve 35, 4Z to open. The valve remains in openposition as long as the control pressure in chamber 71 is high enough tohold pilot valve 63, 111 open, regardless of the pressure at inlet port101. When the pressure of fluid in chamber 71 is insufficient toovercome the force of spring 65, valve 63, 111 is closed, and thepressure in chamber 45 above poppet 37 rapidly builds up through orifice113 until it substantially equals the pressure at inlet port 101,whereupon spring 44 closes valve 35, 42.

In FIGURES 7 through ll there are shown several valves and valve bodiesembodying the principles of the invention but which differ from thevalves and valve bodies shown in FIGURES 1 through 6 in that they aredesigned to operate at pressures up to only 3,000 p.s.i. In eachinstance the various valve bodies are designed to accommodate thestandard sleeve 33 and poppet 37 but are somewhat less heavilyconstructed at critical points as the uid forces to which they aresubjected are not as great.

The cap of the valve shown in FIGURE 7 includes pilot valve structurewhereby the valve 35, 42 is caused to function as a relief valve. Thiscap valve structure differs from that of FIGURES l, 5 and 6 in that itdoes not include a push-off piston. Fluid pressure below poppet 37 isapplied through orifice 92 to chamber 45 above poppet 37, spring 44holding the poppet in contact with seat 35. Fluid at this same pressureis also applied through orifice 121 to the left end of valve element 64tending to urge that element away from its seat 63. When the fluidpressure rises to a point such that the hydraulic force tending to openvalve 63, 64 exceeds the force of spring 65, which is determined by thesetting of adjusting screw 66, valve element 64 is moved away from itsseat 63, so that the pressure above poppet 37 drops, since chamber 74 tothe right of seat 63 is connected to outlet port 23 throughcommunicating passages 122 and 123 in the valve cap and bodyrespectively. Flow from inlet port 124 through orifice 92 tending toreduce the low 9 pressure in chamber 45 is restricted by the narrow sizeof orifice 92, and the valve 35, 42 remains open as long as the forceexerted by fluid in chamber 125 on valve element 64 is greater than theforce of spring 65. The valve remains in this condition until pressureapplied at inlet port 124 drops below a predetermined value.

In FIGURES 8-11 are illustrated various types of valve bodies capable oflhanding pressures up to 3000 p.s.i. at various flow rates when fittedwith standard closure forming members 33, 37 and a cap 120 such as thatshown in FIGURE 7. It will be appreciated that the cap 120 can bemodified to provide a sequence or unloader control function bymodification as above described in connection with FIGURES and 6. Highspeed response is achieved in all these valves.

By reason of the previously described difference in the areas of poppet37 which are acted upon by opposing pressures when the valve is closed,it is possible that if the pressure at outlet port 23 should exceed thepressure at inlet port 22, a valve of the type shown in FIGURE 1 mightopen and permit reverse flow. This may be explained by a specificillustration- If the force of spring 44 is about 50 pounds, and if thedifferential in areas is about 3%, and further if the cross-sectionalarea of the spool is one square inch, then an excess of pressure atoutlet port 23 over the pressure at inlet port 22 will act upwardly onan area of .03 square inch. If the pressure at port 22 is atmosphericpressure and the pressure at port 23 is about 1670' pounds, then theunbalanced opening pressure will be in excess of 5() pounds and willexceed the closing force of 50 pounds applied by the spring, causing thevalve to open.

For this reason, if the valve is to be used in a circuit in which it islikely to be subjected to reversed pressure conditions, that is,conditions in which pressure at port 23 which is greater than thepressure at port 22, we

prefer to use a valve wherein the area difference is of the order ofabout 0.541%. When the area differential is in this range, theunbalanced pressure at port 23 tending to open the valve will not supplya very large force in relation to the force of spring 44. Actual testshave demonstrated that at pressures up to about 5000 p.s.i. the valvewill not open where the area differential is about .67%. Those skilledin the art will realize that similar results might also be effected ybyusing a spring 44 of greater force, but that is undesirable inasmuch asit tends` to make the operation of the valve more sluggish.

FIGURE 13 illustrates a valve in accordance with this invention whichincludes alternative means in the form of check valves whereby it isadapted for use in a system in which the pressure conditions may becomereversed. The check valve means of the valve shown in FIGURE 13 enableany valve in accordance with this invention to be used under reversepressure conditions, regardless of the area differential of the poppetor of the force of the spring.

In the past it has occasionally been necessary to utilize a separatecheck valve connected to the outlet port, to permit ow from the outletport but not toward the outlet port, so that an excess of pressure inthe outlet linewould not be reected past the check valve to the poppetto tend to cause the valve to open. However, such check valvesnecessarily carried the full ow of the valve, and on that account werequite large and bulky and were undesirable where space was at a premium.

The novel check valve means we have invented are very compact, andpreferably are iitted as an integral part of the valve in the form asandwich plate between the upper face 26 of the valve body 20 and thelower surface of cap 50.

FIGURE 13 illustrates a preferred embodiment of a check valve means inaccordance with this aspect of our invention. This valve includes acheck valve permitting flow from the inlet port to chamber 45 but lnotin the reverse direction, and a second check valve permitting ow 10 fromthe outlet port to chamber 45, but not in the reverse direction.

The valve body 20 and each of the elements contained therein mayconform, for purposes of description, to the valve body previouslydescribed in connection with FIG- URE 1, although the principles of thisaspect of the invention are not limited to that valve body alone but infact are also equally applicable to the other valve bodies shown in theother iigures. Similarly, the control cap 50 corresponds to the capillustrated in FIGURE 1, and enables the valve to function as a reliefvalve,

The check valves are advantageously contained in a sandwich plate 125,having parallel upper and lower surfaces, which is secured between thecap 50 and valve body 20 by suitable fastening means not shown. Ahorizontal bore 126 in the cap is intersected at its right end by avertical bore 127 which communicates with vertical bore 57 of the valvebody and with vertical bore 56 of the cap. A second vertical bore 128intersects horizontal bore 126 of the sandwich plate adjacent its leftend, and communicates between vertical passage 25 of the valve body andvertical bore 53 of the cap 50. A third vertical bore 129 in thesandwich plate communicates from bore 54 of the cap to the chamber 45above spool 37 in the valve body, but this bore 129, which is indicatedby dashed lines in FIGURE 13, does not intersect bore 126.

A ball seat element 131 is fitted in bore 128 of the sandwich plate, andthis ball seat element includes a downwardly sloping shoulder surface132 with which a ball 133 coacts to forni a check valve permitting flowfrom bore 25 to bore 126 but not in the reverse direction.

At the right end of bore 126 a ball seat element 135 is secured. Thisball seat element has an axial bore which includes a restrictor ororifice 136. A plug 137 is threaded in bore 126 and bears against theright end of ball seat element holding that element against a shoulderin bore 126. Radial ports 138 extend from the axial bore in ball seatelements 135 to vertical passageway 127. A shoulder surface 140 isformed at the left end of restrictor 136, and a ball 141 coacts with theshoulder surface 140 to form a check valve permitting flow from bore 127toward bore 128 but not in the reverse direction.

When the pressure at the valve inlet port 22 is greater than thepressure at outlet -port 23, this pressure is reected through restrictor31, vertical passageway 25, through the open check valve 132, 133 invertical bore 128, through vertical bore 53 to the pilot valve in thecap, and the pilot valve functions in the previously described manner.Check valve 140, 141 is closed and prevents flow from bore 126 to theoutlet port. When the pressure vat port 22 exceeds the value at whichthe pilot valve 63, 64 is set to open, that valve opens and releases theexcess fluid to vertical passageways 56,127 and 57, to the low pressureport 23.

When the pressure at the normal outlet port 23 exceeds the pressure atport 22, the pressure is reflected upwardly through passageways 57 and127 into bore 126. The check valve 140, 141 in the sandwich platepermits flow from bore 57 to bore 53 and this pressure is appliedthrough piston 62 to passageways 54 and 129 into chamber 45. Check valve132, 133 prevents ow from bore 126 to port 22. The iluid in chamber 45is thus trapped, and cannot be displaced to permit the srpool to liftregardless of the excess of fluid force tending to open the valve.

lOne of the advantages of this construction is that the main flow of thevalve does not pass through the check valves in the sandwich plate,thereby enabling check valves of small size to be utilized, incomparison with past arrangements wherein the full ow of the valve under-normal conditions did pass through the check valve.

It is contemplated that the check valve means we have invented may beused alternatively to the valve construction previously describedwherein the area dilerential was small enough in relation to the size ofthe spring that the valve would not tend to Open under expected reversepressure conditions.

While the preferred embodiment of the invention has been describedherein, the invention is not limited to that form alone but includesother modifications and embodiments within the scolpe of the claimswhich follow.

We claim:

i. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber at one endthereof, an outlet port extending laterally from said chamber, acylindrical valve member slidably received in said chamber, said valvemember having a diameter larger than that of said inlet port and havingan endwise portion seating in edge contact against said inlet port,elastic means biasing said valve member toward said inlet port, arestricted tiuid passage communicating between said inlet port and saidchamber at the end of said valve member is opposite to said endwiseportion, the area of said valve member which is subjected to pressure insaid chamber at the end of said valve member opposite to said endwiseportion being greater by about 0.5 to about 6 percent than the area ofthe endwise portion of said valve member which is subjected to pressureat said inlet port when said valve is closed, and a pilot Valve adaptedto release pressure in said chamber at the end of said valve memberwhich is opposite to said endwise portion when pressure in said chamberequals a predetermined value.

2. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber axially at oneend thereof, said inlet port presenting a sharp annular seating edge, anoutlet port extending laterally from said chamber, a cylindrical valvemember slidably received in said chamber7 said Valve member having aconically tapered endwise portion seating in line 'Contact against saidedge, elastic means biasing said valve member toward said edge, owrestricting passage means reflecting pressure at said inlet port intosaid chamber at the end of said valve member which is opposite to saidendwise portion, the area of said valve member which is subjected topressure in said said chamber at the end of said valve member oppositeto said endwise portion being greater by at least about 0.5 to about 6percent than the area within said seating edge, and adjustable pilotvalve means releasing excess fpressure in said chamber at the end ofsaid valve member which is opposite to said endwise portion when thepressure in said chamber equals a predetermined value, said valve memberbeing in substantial hydraulic balance when said valve member is openand being subjected to a net closing lpressure when closed which isproportional to the pressure at said inlet port.

3. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber at one endthereof and presenting an annular seat, an outlet port extendinglaterally from said chamber, a cylindrical valve member slidablyreceived in said chamber, said valve member having a first endwiseportion seating against said seat of said inlet port and a secondendwise portion in said chamber opposite thereto, elastic means biasingsaid valve member toward said inlet port, a flow restricting uid passagecommunicating between said inlet port and said second endwise portion ofsaid valve member, the area of said second endwise portion being greaterby about 0.5 to about 6 percent than the area of said rst endwiseportion of said valve member which is subjected to pressure at saidinlet port when said valve is closed, and a pilot valve adapted torelease excess fluid Iunder pressure acting on said second endwiseportion of said valve mem-ber when pressure at said inlet port equals apredetermined value.

4. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber at one endthereof, said inlet port presenting a sharp annular seating edge, anoutlet port extending laterally from said chamber, a cylindrical valvemember slidatbly received in said chamber, said valve member having acon'ically tapered endwise portion seating in line contact against saidseating edge, said tapered portion forming an angle of more than about10 and less than about 30 with the axis of said cylindrical valvemember, elastic means biasing `said valve member toward said linletport, a restricted fluid passage communicating between said inlet portand `said chamber at the end of said valve member which is opposite tosaid endwise po-rtion, the area of said valve member which is subjectedto pressure in said chamber at the end of said valve member opposite tovsaid endwise portion being greater by at least about 0.5 to about 6percent than the area within said seating edge, and adjustable pilotvalve means releasing pressure in said chamber at the end of said valvemember when said lpressure in said chamber equals a predetermined value.

5. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, .an inlet port entering said chamber at lone endthereof, said inlet port presenting a sharp annular seating edge, an-ou-tlet port extending laterally from said chamber, a cylindrical valvemember slidably received in `said chamber, said valve member having aconically `tapered endwise portion seating in line contact against saidseating edge, said tapered portion forming an angle of about 20 .with anaxis of said cylindrical valve mem-ber, elastic means biasing saidva-lve member toward 'said inlet port, a restricted uid passagecommunicating between said inlet port and said chamber at the end ofsaid Valve member whichis opposi-te to said endwise portion, the area ofsaid valve member which is subjected to pressure in said chamber at theend of said valve member opposite to said endwise portion being greaterby at least about 0.5 to about 6 percent than the area within saidseating edge, and adjustable pilot valve means releasing pressure insaid chamber at the end of said valve member when said pressure in saidcham-ber equals a predetermined Value.

`6. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber axially at oneend thereof, said inlet po-rt presenting a sharp annular seating edge,an outlet port extending laterally lfrom said chamber, a cylindricalvalve member slidably received in said chamber, said valve member havinga conically tapered endwise portion seating in line contact against saidedge, la spring biasing said valve member toward said edge, a restricteduid passage communicating between said inlet port and said chamber atthe end of lsaid valve member which is opposite to said endwise portion,the area of said valve member which is subjected to pressure in saidchamber at the end ot .said valve member opposite to said endwisepontion being greater by about 0.5 to 1 percent than the area withinsaid seating edge, and adjustable pilot valve means releasing excess uidunder pressure in said chamber at the end of said valve member which isopposite to said endwise portion when the pressure in said chamberequals a predetermined value, said valve member 'being in substantialhydraulic balance when said valve member is open and being subjectedwhen closed lto a net clos-ing fluid force which lis `small in rela-tion-to the force tending to close the valve member and which isproportional to the lpressure at said inlet port, said difference inareas -being insufficient in relation to 'the force of said spring tocause said valve member to open when pressure at said outlet portexceeds the pressure at said inlet port, up to a predetermined pressureat said outlet port.

7. A Valve compris-ing a valve body having a right cylindrical chamberformed therein, a sleeve coaxially received in said chamber, an inletport entering said chamber at one end thereof, said sleeve presenting aninwardly extending annular seat adjacent said inlet port,

said seat having a right angular seating edge, an outlet port extendinglaterally from said chamber through said sleeve downstream of butadjacent to said seat, a cylindrical poppet slidably disposed in saidsleeve, said poppet having at one end 'thereof a tapered edgewiseportion seating in line contact against said edge, the crosssectionalarea of said poppet being about 0.5 to 1% greater than the internal areawithin said right angular seating edge of said seat, the angulation ofsaid tapered edgewise portion being about 20 from the axis of saidpoppet, iiuid pressure at said inlet port tending to open said valve,uid pressure at the end of said poppet which is opposite said seattending to close said valve, a rst fluid passage including a restrictedorifice for statically balancing the fluid pressures acting on the endsof said poppet, spring means biasing said poppet toward said seat, adrain passage, a second iiuid passage communicating between said firstpassage and said drain passage, said second passage including a pilotvalve adapted to open at a predetermined pressure to release thepressure acting on the end of said poppet which is opposite said seatand thereby hydraulically unbalance the uid pressures acting on the endsof said poppet causing said poppet to open, the difference in areasbeing insuicient in relation to the force of sa-id spring means to causesaid poppet to open in response to a high pressure at said outlet portrelative to said inlet port up to a predetermined maximum pressure atsaid outlet port.

8. A hydraulic valve comprising, a body having a chamber formed thereinand having inlet and' outlet ports communicating with said chamber,sa-id inlet port providing a seat extending in a plane generallytransverse to the axis of the flow of fluid through said inlet port tosaid chamber, said seat presenting an annular seating edge, acylindrical valve member movable in said chamber and having a conicaltaper at one end which is cooperable in line contact with said seat forclosure, of said valve, said taper forming an angle more than about andless than about 30 with the axis of said Valve member, said valve memberbeing urged away from said seat by iiuid pressure at said inlet port,means including a restricted passageway for reflecting pressure at saidinlet port to the end of said valve member opposite said seat, saidvalve member `being constructed so as to reside in substantial hydraulicbalance in open position with respect to said seat when exposed to thepressure at said inlet port and the pressure reflected through said pas-Sageway, the area of said cylindrical valve member being about 0.5 toabout 6% greater than the area within said seating edge whereby saidValve member is in slight hydraulic unbalance when in closed positionwith respect to said seat, spring means biasing said Valve member toclosed posit-ion, and means associated with said valve body forrelieving excess pressure of uid in said passageway and therebyrelieving excess pressure exerted on said valve member through saidpassageway when the pressure in said passageway equals a predeterminedvalue, whereby said valve member becomes unbalanced sufriciently toovercome the spring bias thereof for movement of said valve member awayfrom said seat.

9. A valve comprising a valve body having a right cylindrical chamberformed therein, aV sleeve coaxially received in said chamber, an inletport entering said chamber at one end thereof, said sleeve presenting aninwardly extending annular seat adjacent said inlet port, said seathaving a right angular seating edge, an outlet port extending laterallyfrorn said chamber through said sleeve downstream of but adjacent tosaid seat, a cylindrical poppet slidably disposed in said sleeve, saidpoppet having at one end thereof a tapered edgewise portion seating inline contact against said edge, the cross-sectional area of said poppetbeing about 0.5-6% greater than the internal area within said rightangular seating edge of said seat, the angulation of said taperededgewise portion being about 20 from the axis of said poppet, iluidpressure at said inlet port tending to open said valve, iluid pressureat the end of said poppet which is opposite said seat tending to closesaid valve, a iirst iiuid passage including a restricted orilice forstatically balancing the uid pressures acting on the ends of saidpoppet, spring means biasing said poppet toward said seat, a drainpassage, a second fluid passage communicating between said rst passageand said drain passage, said second passage including a pilot valveadapted to open at a predetermined pressure to release the pressureacting on the end of said poppet which is opposite said seat and therebyhydraulically unbalance the uid pressures acting on the ends of saidpoppet causing said poppet to open.

10. A valve comprising, a valve body having a right cylindrical chamberformed therein, an inlet port coaxially entering said chamber at one endthereof, an annular valve seat between said inlet port and said chamber,said seat presenting a sharp, angular annular seating edge, an outletport extending from said chamber adjacent said seating edge, a poppetslidably received in said chamber, said poppet having a conieallytapered peripheral portion at one end seating in line contact with saidseating edge, said tapered portion forming an angle of more than about10 and less than about 30 with the -axis 0f said poppet, thecross-sectional area of said poppet being about 0.5 to about 6% greaterthan the area within said annular seating edge, said poppet having arestricted fluid passage communicating between its opposite endsurfaces, spring means biasing said poppet toward said seat, and a pilotvalve actuable at a predetermined pressure to release excess iiuid insaid chamber acting on the end of said poppet which is remote from sa-idinlet port, said pilot valve including a seat and a spring-biased valveelement for-ming a valve therewith.

11. A valve comprising, a valve body having a right cylindrical chamberformed therein, an inlet port coaxially entering said chamber at one endthereof, an annular valve seat between said inlet port and said chamber,said seat presenting an annular, sharp angular seating edge, an outletport extending from said chamber adjacent said edge, a cup-shaped poppetslidably received in said chamber, said poppet having at one end aconically tapered peripheral portion seating in line contact with saidseating edge, and forming a valve between said inlet port and saidoutlet port, said tapered portion forming an angle of more than about 10.and less than about 30 with the axis of said poppet, the opposite endof said poppet being subjected to pressure in said chamber, thecross-sectional area of said poppet being about 0.5 to about 6% greaterthan the area Vwithin Said annular seating edge, a fluid passagereiiecting pressure at said inlet port to said opposite end of saidpoppet, and a -pilot valve actuable in response to a predeterminedpressure to release excess fluid under pressure acting on said oppositeend of said poppet, said pilot valve including a seat and aspring-biased valve element forming a valve therewith.

12. A valve comprising, a valve body having a right cylindrical chamberkformed therein, an inlet port coaxially entering said chamber at oneend thereof, an annular valve seat between said inlet port and saidchamber, said seat presenting an annular, sharp angular seating edge, anoutlet port extending from said chamber adjacent said edge, a cup-shapedpoppet slidably received in said chamber, said poppet having at one enda conically tapered peripheral portion seating in line contact with saidseating edge and forming a valve between said inlet port and said outletport, said tapered portion forming an angle of more than about 10 andless than about 30 with the axis of said poppet, the opposite end ofsaid poppet being subjected to pressure in said chamber, thecross-sectional area of said poppet being about 0.5 to about 6% greaterthan the area within said annular seating edge, a restricted iiuidpassage reflecting pressure at said inlet port to said opposite end ofsaid poppet, spring means biasing said poppet toward said edge, and apilot Valve actuable in response to a predetermined pressure to releaseexcess uid under pressure acting on said opposite end of said poppet,said pilot valve including a seat and a spring-biased valve elementforming a valve therewith, said poppet being utilizable in a series ofsaid valve bodies of different sizes all having cylindrical chambers ofequal sizes formed therein.

13. A valve comprising, a valve body having a right cylindrical chamberformed therein, an inlet port coaxially entering said chamber at one endthereof, an annular valve seat between said inlet port and said chamber,said seat presenting a sharp, angular annular seating edge, an outletport extending laterally from said chamber, a poppet slidably receivedin said chamber, said poppet having a conically tapered endwise portionseating in line contact with said seating edge, said tapered portionforming an angle of more than about 10 and less than about 30 with theaxis of said poppet, the cross-sectional area of said poppet being about0.5 to about 6% greater than the area within said annular seating edge,a restricted fluid passage communicating between said inlet port andsaid chamber above the end of said poppet which is opposite to saidendwise portion, spring means biasing said poppet toward said seat, apilot valve actuable in response to a predetermined pressure to releaseexcess uid under pressure in said chamber acting on the end of saidpoppet which is opposite to said endwise portion, said pilot valveincluding a seat and a spring-biased valve element forming a valvetherewith, check valve means permitting flow from said inlet port tosaid chamber above the end of said poppet which is opposite to saidendwise portion but not in the reverse direction, and check valve meanspermitting ow from said outlet port to said chamber above the end ofsaid poppet which is opposite to said endwise portion but not in thereverse direction.

14. A valve comprising, a valve body, said body presenting a cylindricalchamber therewithin, an inlet port entering said chamber at one endthereof, an outlet port extending laterally from said chamber, acylindrical valve member slidably received in said chamber, said valvemember having an endwise portion seating in peripheral edge contactagainst said inlet port, elastic means biasing said valve member towardsaid inlet port, a restricted uid passage communicating between saidinlet port and said chamber at the end of said valve member which isopposite to said endwise portion, the area of said valve member which issubjected to pressure in said chamber at the end of said valve memberopposite to said endwise portion being greater by about 0.5 to about 6percent than the area of the endwise portion of said valve member whichis subjected to pressure at said inlet port when said valve is closed, apilot valve adapted to release excess pressure in said chamber at theend of said valve member which is opposite to said endwise portion whenpressure in said chamber equals a predetermined value, said pilot valvehaving an inlet side and an outlet side, ya check valve between saidinlet port and the inlet side of said pilot valve permitting flow towardsaid inlet side but not in the reverse direction, and a passagewayincluding a second check valve communicating between said outlet portand said inlet side, said second check valve permitting iiow toward saidinlet side but not in the reverse direction.

15. A valve comprising, la valve body, said body presenting acylindrical chamber therewithin an inlet port entering said chamber atone end thereof, an outlet port extending laterally from said chamber, acylindrical valve member slidably received in said chamber, said Valvemember having a iirst endwise portion seating in peripheral edge contactagainst said inlet port and a second endwise portion in said chamberopposite thereto, elastic means biasing said valve member toward saidinlet port, a restricted fluid passage communicating between said inletport and said second endwise portion of said valve member, said passageincluding check valve means permitting iiow toward said second endwiseportion but not away therefrom, the area of said second endwise portionbeing greater by about `0.5 to about 6 percent than the area of saidfirst endwise portion of said valve member which is subjected topressure at said inlet port when said valve is closed, a pilot valveadapted to release excess fluid under pressure acting on said secondendwise portion of said valve member when pressure at said inlet portequals a predetermined value, and check valve means permitting flow fromsaid outlet port toward said second endwise portion but not in theopposite direction.

16. A valve comprising a v-alve body having a right cylindrical chamberformed therein, a sleeve coaxially received in said chamber, an inletport entering said chamber at one end thereof, said sleeve presenting aninwardly extending annular sea-t adjacent said inlet port, said seathaving a right angular seating edge, an outlet port extending laterallyfrom said chamber through said sleeve `downstream of but adjacent tosaid seat, a cylindrical poppet slidably disposed in said sleeve, saidpoppet having at one end thereof a tapered edgewise portion seating inline contact against said edge, the cross-sectional tarea of said poppetbeing about 0.5-6% greater than the internal area within said rightangular seating edge of said seat, the angulation of said taperededgewise portion being `about 20 from the axis of said poppet, fluidpressure at said inlet port tending to open said valve, fluid pressureat the end of said poppet which is remote from said seat tending toclose said valve, a iiow restricting first fluid passage communicatingbetween said inlet port and the end of said poppet which is remote fromsaid seat Ifor statically balancing the fluid pressures acting on theends of said poppet in response to pressure at said inlet port, said rstpassage including a first check valve preventing flow in the directiontoward said inlet port, spring means biasing said poppet toward saidseat, a pilot valve contained in a cap, said pilot valve having an inletside and an outlet side, said inlet side communicating with the end ofsaid poppet which is remote from said seat, said `outlet sidecommunieating with said outlet port, said pilot valve being adapted toopen at a predetermined pressure to release excess pressure acting onthe end of said poppet which is remote from said seat, and a secondpassage communicating between said outlet port and the inlet side ofsaid pilot valve, said second passage including a second check valvepreventing flow toward said outlet port, said irst and second checkvalves and said second passage being contained in a sandwich platemounted between said cap and said valve body.

17. A valve comprising, a valve body having a right cylindrical chamberformed therein, a sleeve coaxially received in said chamber, an inletport entering said chamber at one end thereof, said sleeve presenting aninwardly extending annular seat Aadjacent said inlet port, said seathaving a right angular seating edge, an outlet port extending laterallyfrom said chamber through said sleeve downstream of but adjacent to saidseat, a cylindrical poppet slidably disposed in said sleeve, said poppethaving at one end thereof a tapered edgewise portion seating in linecontact against said edge, the cross-sectional area of said poppet beingabout 0.5-6% greater than the internal area within said right angularseating edge of said seat, the angulation of said tapered edgewiseportion being about 20 from the axis of said poppet, fluid pressure atsaid inlet port tending to open said valve, iiuid pressure at the end ofsaid poppet which is opposite said seat tending to close said valve, afirst uid passage including a restricted orifice and a check valvepreventing flow toward said inlet port and statically balancing the uidpressures acting on the ends of said poppet in response to pressure atsaid inlet port, spring means biasing said poppet toward said seat, apilot valve yhaving an inlet side and an outlet side, said inlet sidecommunicating with the end of said poppet which is remote from saidseat, the outlet side of said pilot valve communicating with said outletport, said pilot valve being adapted to open at a predetermined pressureto release excess pressure at said inlet side, and a second passagecommunicating between said outlet port and the inlet side of said pilotvalve, said second passage including a check valve permitting ow towardsaid inlet side and preventing flow in the opposite direction.

18. In combination, a series of hydraulic Valve bodies of differentsizes, each body presenting -a chamber, the chamber of all of saidbodies being equal in size, an inlet port entering said chamber at oneend thereof, means defining an annular seat adjacent said inlet port,said seat presenting a sharp angled seating edge the plane of which isperpendicular to the axis of flow through said inlet port, an outletport extending laterally from said chamber, a cylindrical poppet adaptedto be selectively received in the said chamber of each of said bodies,said poppet having a tapered peripheral portion forming a closure inline contact with said edge, said tapered portion forming an angle ofbetween and 30 with the axis of said poppet, the cross-sectional area ofsaid poppet being slightly greater than the area within said seatingedge, passage means including a restricted orifice communicating betweensaid inlet port and the end of said poppet which is opposite to saidseat, a spring biasing said poppet toward said seat, a supplementalvalve control cap adapted to be selectively removably fastened to eachbody of said series, said cap including a drain port and a passagewaycommunicating between said drain port and the end of said poppet whichis opposite to said seat, valve means in said passageway adapted to openat predetermined pressure to release to said drain port the pressure offluid at the end of said poppet which is opposite to said seat, thebodies of said series and the inlet ports and outlet ports thereofdiffering in size from body to body whereby the bodies of the series arerespectively adapted for installation in hydraulic lines of differentsizes, said chamber and poppet being of a size sufiicient to accommodatethe highest pressure and ow requirements to be served by the largestbody of the series.

19. In combination, a series of hydraulic valve bodies of differentpressure ratings and fiow capacities, each body presenting a chamber,the chambers of the bodies of said series being uniform in size, eachbody also having an inlet port entering said chamber at one end thereof,a cylindrical sleeve adapted to be disposed within the said chamber ofeach body of said series, said sleeve presenting a seat adjacent saidinlet port, said seat residing in a plane which is perpendicular to theaxis of ow through said inlet port and presenting an inwardly offsetannular seating edge, an outlet port extending laterally from saidchamber through said sleeve, a cylindrical poppet slidably received insaid sleeve, said poppet having at one end thereof a tapered peripheraledge forming a valve with said seating edge, the angle of said taperededge being between 10 and 30, the crosssectional area of said poppetbeing about 0.5-6% greater than the area within said seating edge, uidpressure at said inlet port tending to open said valve, a passageincluding a restricted orifice communicating between said inlet port andthe end of said poppet which is opposite to said inlet port, said poppetwhen in open position presenting substantially equal areas to pressureat said inlet port and at the end of said poppet which is opposite tosaid inlet port, a spring biasing said poppet toward said seat, a valvecontrol cap adapted to be fastened to each body of said series, said capincluding a relief valve adapted to open when the pressure at the end ofsaid poppet which is opposite to said inlet port exceeds a predeterminedvalue, the bodies of said series and the inlet ports and outlet portsthereof differing in pressure rating and flow capacity whereby thebodies of the series are respectively adapted for installation inhydraulic lines of different flow capacities and pressures, saidchamber, poppet and sleeve being sufliciently large to accommodate thehighest pressure and flow requirements to be served by the largest bodyof the series.

`20. A hydraulic Valve comprising a body selected from a series ofbodies of different pressure ratings and ow capacities, each bodypresenting a chamber, an inlet port entering said chamber at one endthereof, a cylindrical sleeve disposed within said chamber, said sleeveincluding a seat adjacent said inlet port, said seat presenting aninwardly offset annular right angled seating edge, said edge residing ina plane which is perpendicular to the axis of iiow of fluid through saidinlet port into said chamber, an outlet port extending laterally fromsaid chamber through said sleeve, a cylindrical poppet slidably receivedin said sleeve, said poppet having at one end thereof an angulatedannular seating surface forming a valve with said seating edge, theangle of said angulated surface being between about 10 and 30, thecrosssectional area of said poppet being about 0.5% to 6% greater thanthe area Within said seating edge, fluid pressure at said inlet porttending to open said valve, said poppet including a restricted passagecommunicating between its opposite ends, said poppet in open positionpresenting substantially equal areas to pressure at each end, a springbiasing said poppet toward said seat, a valve control cap removablyfastened to said body, said cap including a pressure actuated pilotvalve adapted to open when the pressure at the end of said poppet whichis opposite to said inlet port exceeds a predetermined value, the bodiesof said series and the inlet ports and outlet ports thereof differing inpressure rating and flow capacity from body to body whereby the bodiesof the series are respectively adapted for installation in hydrauliclines of different flow capacities and pressures said chamber, poppetand sleeve being suiciently large to accommodate the highest pressureand flow requirements to be served by the largest body of the series.

References Cited UNITED STATES PATENTS 2,366,596 1/1945 Clifton 137-4912,480,712 8/1949 Carbon 251-43 X 2,724,406 11/ 1955 Murray 137-4912,747,606 5/1956 Adams 137--489.5 2,661,017 12/1953 Geiger 137-4912,661,763 12/ 1953 Renick 137-489 2,737,974 3/1956 Renick 137-489WILLIAM F. ODEA, Primary Examiner.

R. GERARD, Assistant Examiner.

1. A VALVE COMPRISING, A VALVE BODY, SAID BODY PRESENTING A CYLINDRICALCHAMBER THEREWITHIN, AN INLET PORT ENTERING SAID CHAMBER AT ONE ENDTHEREOF, AN OUTLET PORT EXTENDING LATERALLY FROM SAID CHAMBER, ACYLINDRICAL VALVE MEMBER SLIDABLY RECEIVED IN SAID CHAMBER, SAID VALVEMEMBER HAVING A DIAMETER LARGER THAN THAT OF SAID INLET PORT AND HAVINGAN ENDWISE PORTION SEATING IN EDGE CONTACT AGAINST SAID INLET PORT,ELASTIC MEANS BIASING SAID VALVE MEMBER TOWARD SAID INLET PORT, ARESTRICTED FLUID PASSAGE COMMUNICATING BETWEEN SAID INLET PORT AND SAIDCHAMBER AT THE END OF SAID VALVE MEMBER IS OPPOSITE TO SAID ENDWISEPORTION, THE AREA OF SAID VALVE MEMBER